检查字典中是否存在键
If oDic.Exists("US") Then
    msgbox "The Key US Exist. The value is " + oDic("US")
Else
    msgbox "Key Does not exist."
End If 
If oDic.Exists("US") Then
    msgbox "The Key US Exist. The value is " + oDic("US")
Else
    msgbox "Key Does not exist."
End If